Kinetic energy is the energy that a body possesses due to its movement. So it is the capacity or work that allows an object to go from being at rest, or still, to moving at a certain speed.

In other words, the kinetic energy of an object is that which is produced due to its motion and depends on its mass and velocity as follows:

$Ec=\frac{1}{2} *m*v^{2}$

where the kinetic energy Ec is measured in joules (J), the mass m is measured in kilograms (kg) and the velocity v in meters/second (m/s).

In this case you know that a 20 kg curling stone is sliding in a positive direction at 4 m/s. So:

m= 20 kg
v= 4 m/s

Replacing you have:

$Ec_{1} =\frac{1}{2} *20 kg*(4\frac{m}{s}) ^{2}$

Ec₁= 160 J

A second curling stone slides at the same speed but in the opposite direction. So:

m= 20 kg
v= - 4 m/s

Replacing you have:

$Ec_{2} =\frac{1}{2} *20 kg*(-4\frac{m}{s}) ^{2}$

Ec₂= 160 J

The kinetic energy of the two stones is calculated as:

Ec= Ec₁ + Ec₂

Ec= 160 J + 160 J

Ec= 320 J

<u><em>The kinetic energy of the two stones is 320 J</em></u>

7 0

3 years ago

When a sample of a gas is heated in a sealed, rigid container from 200. K to 400. K, the pressure exerted by the gas is:

gavmur [86]

When a sample of a gas is heated in a sealed, rigid container from 200 degree Kelvin to 400 degree Kelvin, the pressure exerted by the gas is increased by a factor 2. Heating any gas actually increases the volume of the gas within a container. As the temperature of the gas rises, the molecules of the gas start moving faster and start striking the walls of the container in which it is kept with more force. The volume of the container tries to expand to accommodate the fast colliding molecules of the gas.

5 0

3 years ago